Technical Field
The present disclosure relates to a stator of a motor and an inner rotor-type motor including the stator.
Background Art
A stator structure of a motor including a plurality of core pieces annularly arranged along the circumferential direction of the motor has been known. Each of the plurality of core pieces includes an arcuate portion having an arcuate shape and a tooth part projecting radially inward from the arcuate portion. The arcuate portion includes a contact portion provided at an end portion on the circumferential direction side of the core piece, the contact portion being in contact with the core piece adjacent thereto, and a cutout portion formed on the radially outer side of the contact portion. The cutout portion is formed at a dimension for preventing the plurality of core pieces from coming into contact with one another when the core pieces are developed linearly. The stator structure further includes a coil wound around the tooth part in each of the plurality of core pieces and an insulator that insulate the plurality of core pieces and the coils from each other. The insulator includes a covering portion that covers each of the plurality of core pieces and an extending portion that extends from the covering portion along a rotating shaft of the motor. A connecting wire that connects a coil wound on one core piece among the plurality of core pieces and a coil wound on another core piece passes a position of a radially outside of the extending portion of the one insulator and generally overlapping a boundary between the contact portion of the one core piece and the cutout portion of the other core piece (see Japanese Patent Application Laid-Open No. 2014-075907).
Incidentally, when the diameter of a coil wound on a stator is small, a film for insulation provided on the surface of the coil is thin. Therefore, when an end portion of the coil is soldered to a terminal such as a power supply terminal or a common terminal of a motor, since the film melts, removal of the film is simultaneously performed and the coil and the terminal become conductive.
However, when a coil having a large diameter is used in order to feed a large current to the motor for the purpose of an increase in an output of the motor, since the thickness of a film provided on the surface of the coil increases, it is difficult to remove the film in a process for soldering the end portion of the coil to the terminal.
As a method of solving such a situation in the removal of the film, there is a method called fusing caulking for holding the end portion of the coil with the terminal and feeding an electric current while compressing the end portion of the coil to melt the film of the coil with heat generated at that time and firmly attaching and connecting the end portion of the coil to the terminal while securing conduction between the end portion of the coil and the terminal.
However, in order to use this method, it is necessary to provide a U-shaped turn-back (a hook portion) in the terminal such that the end portion of the coil can be held. In the case of the thick coil having the large diameter for the purpose of feeding a large current, since the hook portion has to hold the thick coil, the width of the hook portion itself increases.
The thickness of the terminal itself is also increased according to the large current. Therefore, the width of the terminal including the hook portion further increases.
Then, when the terminal is fixed to the stator, in a small motor, it is difficult to secure, above an end face in the axial direction, a sufficient distance for receiving the width of the terminal including the hook portion. The hook portion is located to protrude above a portion on which the coil of the stator is wound. The hook portion hinders turning of a nozzle of a winder that winds the coil. Therefore, the winding of the coil cannot be easily performed.